Imaging the brain during coughing: a unique PET study of cough

2439 

Abstract Submission 

Yasuomi Ouchi^1,2, Takafumi Sugi¹, Etsuji Yoshikawa³

¹Hamamatsu University School of Medicine, Hamamatsu, Japan, ²Hamamatsu Medical Photonics Foundation, Hamamatsu, Japan, ³Hamamatsu Photonics KK, Hamamatsu, Japan

Yasuomi Ouchi  
Hamamatsu University School of Medicine|Hamamatsu Medical Photonics Foundation
Hamamatsu, Japan|Hamamatsu, Japan

Takafumi Sugi  
Hamamatsu University School of Medicine
Hamamatsu, Japan

Etsuji Yoshikawa  
Hamamatsu Photonics KK
Hamamatsu, Japan

Coughing is known as a defensive reflex that protects the airways from harmful substances. Clinically, the cough reflex may be impaired by stroke While brain activity during cough was previously examined by functional magnetic resonance imaging (fMRI) with model analysis, this method does not capture the actual brain activity during coughing. To obtain accurate measurements of brain activity during coughing, we use an unrestrained positron emission tomography (PET) system with head motion correction to correct for head motion while a whole-brain scan was performed during a coughing task.

Twenty-four healthy right-handed men underwent multiple PET scans with [15O]H2O. We have recently developed a PET camera with a free-moving function that enables imaging during head movement by collecting positron signals every 1 second while correcting head movement every 4 milliseconds (Inubushi et al, Neuroimage 2021). Four tasks were performed during the scan: "resting"; "voluntary cough (VC)", which is simply repeated spontaneous coughing; "induced cough (IC)", where participants cough in response to the stimulating stimulus using the cough-inducing method with tartaric acid (CiTA); and "suppressed cough (SC)," in which cough was suppressed in response to CiTA. For CiTA, a 10% solution of L-tartaric acid was used in the IC and SC tasks, and saline was used as a placebo in the resting and VC tasks. We used 60 s of [15O]H2O data reconstructed after the increase in the PET count of the brain. The dose of [15O]H2O injected was 2.5 MBq/kg per scan. During the [15O]H2O experiment, the number of coughs and the intensity of coughing (cough peak flow) were measured. At the end of each scan, the urge to cough during the task was checked on a 10-point scale using the numerical rating scale. We performed whole brain analyses of [15O]H2O PET data with SPM12, applying a fixed-effect analysis with a multi-participant and multi-condition full factorial design, incorporating all scans from all participants into a single general linear model. This study was approved by the Hamamatsu University School of Medicine Ethics Committee.

Whole brain analyses of motion-corrected data revealed that VC chiefly activated the supplementary motor cortex and the cerebellum extending to pons. In the IC condition, the infratentorial regions, including the pons, medulla oblongata and cerebellar regions, were activated. In the SC condition, significant activation was found in the superior frontal region covering the sensory cortex and the anterior and middle cingulate cortices. Furthermore, CiTA-related tasks (IC and SC) activated the higher sensory regions of the cerebral cortex and associated brain regions. When the urge to cough was taken into account in this analysis, we found that a wider range of cerebral regions including the cerebral cortex and diencephalon play a role in cough control under sensory stimulation.

Our PET system allows us to image brain activity without head restriction, and this study is the first to depict brain activity during coughing, suggesting that brain activity during simple cough is controlled chiefly by infratentorial areas. Cough control requires incorporating higher sensory areas of the brain to provide top-down control of information coming from the periphery. The current study partly clarified the underlying mechanism of CiTA, which allows clinicians to predict whether it will be effective before attempting it in stroke patients with brain lesions related to cough control.

PET ¹

Perception: Multisensory and Crossmodal ²

Brainstem

Cerebellum

Cerebral Blood Flow

Data analysis

Perception

Positron Emission Tomography (PET)

Other - cough